A recent judgment in a long-running dispute over plans to develop a site in North Point may offer hope to Mei Foo residents fighting a proposed high-rise building near their homes.

The Court of First Instance in February threw out arguments by a company that said it could make use of unused development rights from Carson Mansion in King's Road to develop an adjacent lot that was originally part of the same site.

It said that if the entire development potential available to a site was not used, the unused part could not be said to 'remain' with one of the component lots.

Barrister-legislator Audrey Eu Yuet-mee said yesterday the same reasoning could be applied to the Mei Foo case, in which a company wants to develop a former LPG storage site next door.

Opponents of the plan are meeting lawyers to discuss the case this week after staging a protest at the private housing estate on Sunday.

In the Carson Mansion case, a triangular lot had been left vacant for years because it was earmarked for an MTR station, but the station plan was dropped and a company bought the unused lot. The company wanted to use 650 square feet in floor area of development potential not used on the Carson site due to previous government miscalculations.

In rejecting the claim, Mr Justice Anselmo Reyes cited a 1983 Privy Council case, saying the company would have to own the original Carson Mansion site or buy it to be able to claim use of its unused development potential.

He had 'sympathy' with the argument of the lawyer representing buildings officials - that the development potential of a site was worked out on site's area as a whole. If the entire development potential of a site was not used, then the unused part could not be said to 'remain' with one of the component lots. Reyes added that 'the argument may apply to most development sites'.

Eu said the building density of Mei Foo Phase 8 was calculated in the 1970s based on a site area comprising the 10 blocks and the LPG plant. 'The plant site contributed to the Phase 8 project. The two parts are tangled together,' she said. 'If you now treat the LPG site as separate, you'll have to get the permission of the owners of Phase 8. Otherwise you'll make Phase 8 an illegal project.'

Billion Star Development, which bought the former LPG plant site from the developers of Mei Foo, New World Development and ExxonMobil Hong Kong, in 2009, got approval in October to build a 20-storey apartment block on the lot.

Residents say they never expected the 1,350-square-metre plant site, which they thought was part of Phase 8, would become the site of a high-rise that would block their views and take up parts of a private street they had paid to maintain.

The government argues there is no issue of 'residual plot ratio' as Billion Star's site is separate, with its own building parameters.

Institute of Surveyors spokesman Lawrence Poon Wing-cheung, while not commenting on the legal issue, said the case illustrated the lack of transparency in the second-hand flat market. 'Buyers have no way to find out whether a site so close to their flats is not part of their housing estate, not to mention whether there are any new buildings coming up,' he said.

Land sale

Billion Star Development bought the former LPG plant site from the developers of Mei Foo in: 2009